An engineer from Nizhny Novgorod patented a cylinder head design in which the geometry of the combustion chamber area directly near the spark plug is changed. The author proposes to round the corner around the spark plug, expecting to improve the movement of the fuel-air mixture, flame propagation, and cleaning of the ignition zone from residual gases.
The key change seems small: the apex of the angle between the plane of the spark plug protrusion and the mating surface of the head to the block is proposed to be rounded.
In the utility model formula, the boundaries of this area are separately defined: one line is located on the mating surface to the block, moving away from the valve axis, and the other passes in a perpendicular plane at a certain distance from the mating surface in the direction of the spark plug hole.
According to the author's idea, the change in shape should affect the movement of the fuel-air mixture in the most sensitive zone of the combustion chamber.
The author associates the proposed geometry with a reduction in losses during mixture formation, more uniform propagation of the flame front, and more complete fuel combustion. Additionally, improved scavenging of the area around the spark plug is claimed, which should reduce the presence of residual combustion products before the next working cycle.
The idea itself fits into a well-known approach in engine building, where the shape of the combustion chamber is used to control charge movement before ignition. The chamber geometry affects turbulence, mixing, and flame propagation path, and the location and shape of the zones near the spark plug are important for ignition conditions.